I went with the implied design.
![[Image: 20hldet.png]](http://i49.tinypic.com/20hldet.png)
Frame 1- Unharmed missile door, missiles not active.
Frame 2- Missiles activated, door unharmed
Frames 5 through 7- Door gradually shatters
Also, although not pictured here, I made it so that the blue that appears when you activate the missile launcher goes away once the door begins to shatter, it makes it look much cleaner.
Frame 1- Unharmed missile door, missiles not active.
Frame 2- Missiles activated, door unharmed
Frames 5 through 7- Door gradually shatters
Also, although not pictured here, I made it so that the blue that appears when you activate the missile launcher goes away once the door begins to shatter, it makes it look much cleaner.